An area of disturbed weather, associated with an elongated area oflow pressure, is located just west of the coasts of Costa Rica andNicaragua. Environmental conditions are forecast to be conducivefor development, and a tropical depression could form during thenext couple of days as the system moves west-northwestward tonorthwestward near the coast of Central America. Regardless ofdevelopment, locally heavy rains are likely over portions of CentralAmerica through Friday.* Formation chance through 48 hours...medium...60 percent.* Formation chance through 5 days...high...70 percent.

$$Forecaster Pasch

Last edited by Macrocane on Fri Oct 27, 2017 1:59 pm, edited 1 time in total.

DISCUSSION AND 48-HOUR OUTLOOK------------------------------At 100 PM CDT (1800 UTC), the center of Tropical Storm Selma waslocated near latitude 11.4 North, longitude 89.5 West. Selma ismoving toward the north-northwest near 5 mph (7 km/h), and thecyclone is expected to turn toward the north by early Saturday.On the forecast track, the center of Selma will approach the coastof El Salvador or Guatemala on Saturday.

Tropical-storm-force winds extend outward up to 45 miles (75 km)from the center.

The estimated minimum central pressure is 1005 mb (29.68 inches).

HAZARDS AFFECTING LAND----------------------RAINFALL: Selma is expected to produce total rain accumulations of3 to 6 inches over El Salvador, southern Guatemala, southernHonduras and far western Nicaragua over the next couple of days.Isolated maximum amounts of 10 inches are possible in El Salvadorand southern Guatemala. This rainfall could cause life-threateningflash floods and mudslides.

WIND: Tropical storm conditions are expected to first reach thecoast within the warning area by early Saturday, making outsidepreparations difficult or dangerous. Tropical storm conditionsare possible within the watch area by early Saturday.

The center of Selma became exposed shortly after the issuance of theprevious advisory, however, deep convection has redeveloped near andjust south of the center this afternoon. The system is feeling theaffects of moderate northeasterly shear and does not appear to havestrengthened. Subjective Dvorak T-numbers from both TAFB and SABare 2.0 (30 kt), however, the initial intensity is maintained at35 kt in agreement with the overnight ASCAT data. Unfortunately,the ASCAT satellites did not pass over the tropical cyclone today.

Satellite and microwave fixes show that Selma has turned morepoleward and is now moving north-northwestward or 345/6 kt. Alarge mid-latitude trough is forecast to move over the Gulf ofMexico tonight and Saturday which should cause Selma to turnnorthward later today or tonight. The 12Z track guidance has comeinto better agreement and brings Selma onshore in El Salvadoror eastern Guatemala on Saturday, and little change was made to theprevious NHC forecast track.

Moderate to strong northeasterly shear is expected to remain overthe tropical cyclone during the next 24 hours, and little overallchange in strength is expected before landfall. Selma shouldrapidly weaken and dissipate over the mountains of Central AmericaSaturday night or Sunday.

It should be noted that the primary threat associated with Selmais heavy rainfall, with totals possibly as high as 10 inchesover portions of El Salvador and Guatemala. This rainfall couldcause life-threatening flash floods and mudslides.